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Electromagnetic PIC codes on unstructured grids

Description: This report discusses the following topics in relationships to plasma simulation: unstructed grids; particle tracking; and field propagation. (LSP)
Date: October 12, 1990
Creator: Ambrosiano, J.J.; Brandon, S.T. (Lawrence Livermore National Lab., CA (USA)) & Loehner, R. (George Washington Univ., Washington, DC (USA). School of Engineering and Applied Science)
Partner: UNT Libraries Government Documents Department
open access

Wideband beam patterns from sparse arrays

Description: Transient radiated fields due to impulsively excited apertures and aperture response due to incident impulsive waves has been the subject of considerable research in acoustics over the last decade. This research is also of importance to wideband radar. Medical ultrasound steered phased arrays use transmitted pulses consisting of from 1 to 3 cycles of a damped sinusoid, which is similar to certain radar systems. As will be shown, planar arrays using ultra-wide band pulses may be formed with very… more
Date: January 12, 1990
Creator: Anderson, F. (Anderson (Forrest), Bernalillo, NM (USA)); Fullerton, L. (Time Domain Systems, Huntsville, AL (USA)); Christensen, W. & Kortegaard, B. (Los Alamos National Lab., NM (USA))
Partner: UNT Libraries Government Documents Department
open access

Initial data from the Soudan 2 experiment

Description: Soudan 2 is an 1100-ton tracking calorimeter which is being built 713 m underground to search for nucleon decay and to study neutrino and cosmic-ray physics. The detector is assembled from 256 identical 4.3-ton calorimeter modules. Each module consists of finely segmented iron and drift tubes, and records three space coordinates and dE/dx for every tube crossing. It is surrounded on all sides by a 1700 m{sup 2} active shield of proportional tubes. The first atmospheric neutrino interactions and… more
Date: October 12, 1990
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department
open access

Assuring both quality and creativity in basic research

Description: How does one assure that both quality and creativity are obtained in basic research environments QA theoreticians have attempted to develop workable definitions of quality, but in more reflective moments, these definitions often fail to capture the deeper essence of the idea of quality.'' This paper asserts that creativity (as a product of the human mind) is a concrete interface between perfunctory definitions of quality (conformance to specifications) and more philosophical speculations about … more
Date: April 12, 1990
Creator: Bodnarczuk, Mark
Partner: UNT Libraries Government Documents Department
open access

Physics data base for the beam plasma neutron source (BPNS)

Description: A 14-MeV deuterium-tritium (D-T) neutron source for accelerated end-of-life testing of fusion reactor materials has been designed on the basis of a linear two-component collisional plasma system. An intense flux (up to 5 {times} 10{sup 18}/m{sup 2}{center dot}s) of 14-MeV neutrons is produced in a fully ionized high-density (n{sub e} {approx equal} 3 {times} 10{sup 21} m{sup {minus}3}) tritium target by transverse injection of 60 MW of neutral beam power. Power deposited in the target is remove… more
Date: October 12, 1990
Creator: Coensgen, F. H.; Casper, T. A.; Correll, D. L.; Damm, C. C.; Futch, A. H. & Molvik, A. W.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear optics with focused x-ray lasers

Description: We have investigated the possibility of focusing x-ray lasers with the use of multilayered mirrors or zone plates. The results indicate that x-ray intensities as high as 10{sup 14} W/cm{sup 2} can be achieved by focusing saturated Ne-like x-ray lasers. These intensities should be adequate for studying nonlinear optical phenomena. 9 refs., 2 figs.
Date: December 12, 1990
Creator: DaSilva, L. B.; Muendel, M. H.; Falcone, R. W.; Fields, D. J.; Kortright, J. B.; MacGowan, B. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Is There Hope for Fusion

Description: From the outset in the 1950's, fusion research has been motivated by environmental concerns as well as long-term fuel supply issues. Compared to fossil fuels both fusion and fission would produce essentially zero emissions to the atmosphere. Compared to fission, fusion reactors should offer high demonstrability of public protection from accidents and a substantial amelioration of the radioactive waste problem. Fusion still requires lengthy development, the earliest commercial deployment being l… more
Date: April 12, 1990
Creator: Fowler, T. K.
Partner: UNT Libraries Government Documents Department
open access

Damped time advance methods for particles and EM fields

Description: Recent developments in the application of damped time advance methods to plasma simulations include the synthesis of implicit and explicit adjustably damped'' second order accurate methods for particle motion and electromagnetic field propagation. This paper discusses this method.
Date: October 12, 1990
Creator: Friedman, A.; Ambrosiano, J.J.; Boyd, J.K.; Brandon, S.T.; Nielsen, D.E. Jr. & Rambo, P.W.
Partner: UNT Libraries Government Documents Department
open access

Weak scale supersymmetry

Description: An introduction to the ideas and current state of weak scale supersymmetry is given. It is shown that LEP data on Z decays has already excluded two of the most elegant models of weak scale supersymmetry. 14 refs.
Date: November 12, 1990
Creator: Hall, L. J.
Partner: UNT Libraries Government Documents Department
open access

Stratospheric ozone conservation by electron attachment to chlorine atoms: The negative-ion chemistry

Description: Creating low-energy electrons in the stratosphere by photoelectric emission has the beneficial effect of suppressing ozone destruction by Cl. This is because Cl is converted to Cl{sup {minus}}, which is less reactive. Critical to the success of this scheme is the ability to attach most of the electrons to Cl{sup {minus}} and its hydrates Cl{sup {minus}} (H{sub 2}O). We found that this attachment efficiency is rather high. This is remarkable given the fact that the electron affinity of Cl{sup {m… more
Date: October 12, 1990
Creator: Ho, D.D.M. (Lawrence Livermore National Lab., CA (USA)); Tsang, K.T. (Science Applications International Corp., McLean, VA (USA)); Wong, A.Y. & Siverson, R.J. (California Univ., Los Angeles, CA (USA). Dept. of Physics)
Partner: UNT Libraries Government Documents Department
open access

Laser-based flow cytometric analysis of genotoxicity of humans exposed to ionizing radiation during the Chernobyl accident

Description: An analytical technique has been developed that allows laser-based flow cytometric measurement of the frequency of red blood cells that have lost allele-specific expression of a cell surface antigen due to genetic toxicity in bone marrow precursor cells. Previous studies demonstrated a correlation of such effects with the exposure of each individual to mutagenic phenomena, such as ionizing radiation, and the effects can persist for the lifetime of each individual. During the emergency response … more
Date: September 12, 1990
Creator: Jensen, R.H.; Bigbee, W.L.; Langlois, R.G.; Grant, S.G. (Lawrence Livermore National Lab., CA (USA)); Pleshanov, P.G. (Ministerstvo Zdravookhraneniya SSSR, Moscow (USSR)); Chirkov, A.A. (Institut Biofiziki, Moscow (USSR)) et al.
Partner: UNT Libraries Government Documents Department
open access

Flashlamp pumping of Nd:glass disk amplifiers

Description: We present experimental results and a model of Nd:glass disk amplifiers which are used in inertial confinement fusion research. We first review our previous measurements on pulsed xenon flashlamps. We then discuss out measurements on the enhancement of the Nd fluorescence decay rate in laser disks by amplified spontaneous emission. Using these data, we have constructed a model of flashlamp pumping which treats the transfer efficiency of pump light from the flashlamps to the disks as an empirica… more
Date: June 12, 1990
Creator: Powell, H. T.; Erlandson, A. C.; Jancaitis, K. S. & Murray, J. E.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear plasma and beam physics in plasma wake-fields

Description: In experimental studies of the Plasma Wake-field Accelerator performed to date at the Argonne Advanced Accelerator Test Facility, significant nonlinearities in both plasma and beam behavior have been observed. The plasma waves driven in the wake of the intense driving beam in these experiments exhibit three-dimensional nonlinear behavior which has as yet no quantitative theoretical explanation. This nonlinearity is due in part to the self-pinching of the driving beam in the plasma, as the dense… more
Date: February 12, 1990
Creator: Rosenzweig, J.B.
Partner: UNT Libraries Government Documents Department
open access

Energy sweep compensation of induction accelerators

Description: The ETA-II linear induction accelerator (LIA) is designed to drive a microwave free electron laser (FEL). Beam energy sweep must be limited to {plus minus}1% for 50 ns to limit beam corkscrew motion and ensure high power FEL output over the full duration of the beam flattop. To achieve this energy sweep requirement, we have implemented a pulse distribution system and are planning implementation of a tapered pulse forming line (PFL) in the pulse generators driving acceleration gaps. The pulse di… more
Date: September 12, 1990
Creator: Sampayan, S. E.; Caporaso, G. J.; Chen, Y. J.; Decker, T. A. & Turner, W. C.
Partner: UNT Libraries Government Documents Department
open access

Performance of a 500 watt Nd:GGG zigzag slab oscillator

Description: Realization of practical multi-kilowatt Nd:garnet lasers will require the scale-up of crystal dimensions as well as more powerful pumping sources. A high average power zigzag slab crystal amplifier testing facility has been established at LLNL which employs two 100 kW{sub e} vortex stabilized arc lamps, cooled reflectors and a cooled, spectrally filtered, crystal slab mounting fixture. The operational characteristics of the first crystal laser to be tested in this setup, a Nd:GGG zigzag oscilla… more
Date: January 12, 1990
Creator: Zapata, L.; Manes, K. R.; Christie, D.; Davin, J.; Blink, J.; Penland, J. et al.
Partner: UNT Libraries Government Documents Department
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